1. Field of the Invention
The present invention relates to an inkjet recording apparatus which performs recording by discharging inks from a recording head having plural discharge opening arrays to a recording material (i.e., a material to which recording is performed), and a new structure of a cleaning unit of the inkjet recording apparatus.
2. Related Background Art
A recording apparatus which has functions as a printer, a copying machine, a facsimile machine and the like or a recording apparatus which is used as an output instrument for a multifunctional electronic apparatus including a computer, a word processor or the like, a work station and the like is configured to record images (including characters, symbols, etc.) on a recording material (or a recording medium) such as paper, cloth, a plastic sheet, an OHP sheet or the like on the basis of recording information. Incidentally, in a serial-type recording apparatus which performs recording while effecting a main scan in the direction perpendicular to a conveying direction of the recording medium, an image is recorded by a recording head (recording means) which is mounted on a carriage moving along the recording medium, sheet feeding is performed by a predetermined pitch after the recording of one line has ended, and thereafter an image of a next line is recorded on the recording material again stopped. Thus, by repeating such operations, the recording on the recording medium is performed as a whole. On one hand, in a line-type recording apparatus which performs recording only in a conveying direction of the recording material, the recording material is first set at a predetermined position, recording of one line is performed, subsequently the recording material is fed by a predetermined pitch, and thereafter recording of a next line is performed. Thus, by repeating such operations, the recording on the recording material is performed as a whole.
Moreover, among the above recording apparatuses, as to an inkjet recording apparatus which performs recording by discharging inks from a recording head to the recording material, the recording means thereof can be easily made compact in size, a high-precision image can be recorded at high speed, and also the recording can be performed on plain paper without any specific process. Moreover, there are advantages that, for example, the running cost is low, noise is of a low level because a non-impact system is adopted, and a color image can be easily recorded by using various kinds of inks (e.g., color inks). In addition, while there are various demands for the material of the recording medium to be used in the inkjet recording apparatus, developments to cope with these demands are advanced in recent years, whereby cloth, leather, nonwoven cloth, and even metal are used in addition to the ordinary recording paper, a resin thin plate (OHP sheet etc.) and the like.
In the inkjet recording apparatus, since the recording is performed by discharging the ink from a minute discharge opening, the ink becomes sticky and is firmly adhered due to evaporation of the ink (i.e., evaporation of solvent) in the vicinity of the discharge opening, the ink and such dust as paper dust or the like are adhered to the surface of the discharge opening, and bubbles are generated and mixed in the ink within the discharge opening. Thus, due to these disadvantages, defective discharge such as unevenness of the discharged ink, non-discharge of ink or the like might occur. To prevent the defective discharge, a cleaning unit (recovery mechanism unit) to maintain and recover the ink discharge performance of the recording head to an excellent state is provided. As a cleaning processing means to be provided in the cleaning unit, a suction recovery means to eliminate plugging by sucking the ink from the discharge opening, a wiping means to wipe off the surface of the discharge opening by rubbing the surface of the discharge opening with a wiper, and the like are generally used.
The suction recovery means covers the discharge opening of the recording head by a cap connected to a suction pump, and also generates a negative pressure in the cap by activating the suction pump. Then, sticky ink, and foreign substance such as bubbles and the like are discharged together with the ink from the discharge opening by means of the negative pressure, and new ink is instead introduced into the discharge opening, thereby maintaining and recovering the ink discharge performance of the recording head. Moreover, the wiping means wipes off and thus eliminates the ink, and foreign substances such as dust and the like which have been adhered to the surface of the discharge opening of the recording head by relatively moving and rubbing the discharge opening of the recording head and the wiper of the cleaning unit with each other.
The wiper is mounted in the wiping means so that it can be moved (i.e., projected and evacuated) on the moving path of the surface of the discharge opening of the recording head. Then, the recording head and the wiper are relatively moved in the state that the wiper is being projected, and wasted ink, dust and the like adhered to the surface of the discharge opening are thus scraped out by the end of the wiper to clean up the surface of the discharge opening, thereby solving the defective discharge, and thus maintaining and recovering the ink discharge performance of the ink discharge opening. Moreover, in the wiping means of the inkjet recording apparatus, such as a color-recording inkjet recording apparatus, a gradation-recording inkjet recording apparatus or the like, which uses the recording head having the plural discharge opening arrays to respectively discharge different kinds of inks, the plural wipers respectively corresponding to the plural discharge opening arrays are used to wipe off the corresponding arrays respectively.
However, conventionally, in the inkjet recording apparatus which includes the cleaning unit (wiping means) to wipe off the plural discharge opening arrays that respectively discharge the different inks by using the plural wipers respectively corresponding to these arrays, it is impossible to effectively prevent the various kinds of inks remaining on the surface of the discharge openings after the wiping process has ended from penetrating into other different ink discharge opening arrays, whereby the following technical problem to be solved occurs. That is, color mixture in which the different inks are mixed together easily occurs, whereby quality deterioration on the recorded image easily occurs due to the color mixture. Moreover, in a case where a convex portion (i.e., a protuberated or protruding portion) and a concave portion which cannot be avoided due to a manufacturing method and an internal structure of the recording head are formed at the end of each discharge opening array, the following technical problem occurs. That is, the wiper runs on the convex portion or is caught by the concave portion, and thus the surface of the discharge opening (particularly the portion corresponding to the discharge opening array) cannot be sufficiently wiped off.